Routing and Mobility on IPv6 over LoWPAN

The IoT means a world-wide network of interconnected objects based on standard communication protocols. An object in this context is a quotidian physical device augmented with sensing/actuating, processing, storing and communication capabilities. These objects must be able to interact with the surrounding environment where they are placed and to cooperate with neighbouring objects in order to accomplish a common objective. The IoT objects have also the capabilities of converting the sensed data into automated instructions and communicating them to other objects through the communication networks, avoiding the human intervention in several tasks. Most of IoT deployments are based on small devices with restricted computational resources and energy constraints. For this reason, initially the scientific community did not consider the use of IP protocol suite in this scenarios because there was the perception that it was too heavy to the available resources on such devices. Meanwhile, the scientific community and the industry started to rethink about the use of IP protocol suite in all IoT devices and now it is considered as the solution to provide connectivity between the IoT devices, independently of the Layer 2 protocol in use, and to connect them to the Internet. Despite the use of IP suite protocol in all devices and the amount of solutions proposed, many open issues remain unsolved in order to reach a seamless integration between the IoT and the Internet and to provide the conditions to IoT service widespread. This thesis addressed the challenges associated with the interconnectivity between the Internet and the IoT devices and with the security aspects of the IoT. In the interconnectivity between the IoT devices and the Internet the problem is how to provide valuable information to the Internet connected devices, independently of the supported IP protocol version, without being necessary accessed directly to the IoT nodes. In order to solve this problem, solutions based on Representational state transfer (REST) web services and IPv4 to IPv6 dual stack transition mechanism were proposed and evaluated. The REST web service and the transition mechanism runs only at the border router without penalizing the IoT constrained devices. The mitigation of the effects of internal and external security attacks minimizing the overhead imposed on the IoT devices is the security challenge addressed in this thesis. Three different solutions were proposed. The first is a mechanism to prevent remotely initiated transport level Denial of Service attacks that avoids the use of inefficient and hard to manage traditional firewalls. It is based on filtering at the border router the traffic received from the Internet and destined to the IoT network according to the conditions announced by each IoT device. The second is a network access security framework that can be used to control the nodes that have access to the network, based on administrative approval, and to enforce security compliance to the authorized nodes. The third is a network admission control framework that prevents IoT unauthorized nodes to communicate with IoT authorized nodes or with the Internet, which drastically reduces the number of possible security attacks. The network admission control was also exploited as a management mechanism as it can be used to manage the network size in terms of number of nodes, making the network more manageable, increasing its reliability and extending its lifetime.A IoT (Internet of Things) tem suscitado o interesse tanto da comunidade académica como da indústria, uma vez que os campos de aplicação são inúmeros assim como os potenciais ganhos que podem ser obtidos através do uso deste tipo de tecnologia. A IoT significa uma rede global de objetos ligados entre si através de uma rede de comunicações baseada em protocolos standard. Neste contexto, um objeto é um objeto físico do dia a dia ao qual foi adicionada a capacidade de medir e de atuar sobre variáveis físicas, de processar e armazenar dados e de comunicar. Estes objetos têm a capacidade de interagir com o meio ambiente envolvente e de cooperar com outros objetos vizinhos de forma a atingirem um objetivo comum. Estes objetos também têm a capacidade de converter os dados lidos em instruções e de as comunicar a outros objetos através da rede de comunicações, evitando desta forma a intervenção humana em diversas tarefas. A maior parte das concretizações de sistemas IoT são baseados em pequenos dispositivos autónomos com restrições ao nível dos recursos computacionais e de retenção de energia. Por esta razão, inicialmente a comunidade científica não considerou adequado o uso da pilha protocolar IP neste tipo de dispositivos, uma vez que havia a perceção de que era muito pesada para os recursos computacionais disponíveis. Entretanto, a comunidade científica e a indústria retomaram a discussão acerca dos benefícios do uso da pilha protocolar em todos os dispositivos da IoT e atualmente é considerada a solução para estabelecer a conetividade entre os dispositivos IoT independentemente do protocolo da camada dois em uso e para os ligar à Internet. Apesar do uso da pilha protocolar IP em todos os dispositivos e da quantidade de soluções propostas, são vários os problemas por resolver no que concerne à integração contínua e sem interrupções da IoT na Internet e de criar as condições para a adoção generalizada deste tipo de tecnologias. Esta tese versa sobre os desafios associados à integração da IoT na Internet e dos aspetos de segurança da IoT. Relativamente à integração da IoT na Internet o problema é como fornecer informação válida aos dispositivos ligados à Internet, independentemente da versão do protocolo IP em uso, evitando o acesso direto aos dispositivos IoT. Para a resolução deste problema foram propostas e avaliadas soluções baseadas em web services REST e em mecanismos de transição IPv4 para IPv6 do tipo pilha dupla (dual stack). O web service e o mecanismo de transição são suportados apenas no router de fronteira, sem penalizar os dispositivos IoT. No que concerne à segurança, o problema é mitigar os efeitos dos ataques de segurança internos e externos iniciados local e remotamente. Foram propostas três soluções diferentes, a primeira é um mecanismo que minimiza os efeitos dos ataques de negação de serviço com origem na Internet e que evita o uso de mecanismos de firewalls ineficientes e de gestão complexa. Este mecanismo filtra no router de fronteira o tráfego com origem na Internet é destinado à IoT de acordo com as condições anunciadas por cada um dos dispositivos IoT da rede. A segunda solução, é uma framework de network admission control que controla quais os dispositivos que podem aceder à rede com base na autorização administrativa e que aplica políticas de conformidade relativas à segurança aos dispositivos autorizados. A terceira é um mecanismo de network admission control para redes 6LoWPAN que evita que dispositivos não autorizados comuniquem com outros dispositivos legítimos e com a Internet o que reduz drasticamente o número de ataques à segurança. Este mecanismo também foi explorado como um mecanismo de gestão uma vez que pode ser utilizado a dimensão da rede quanto ao número de dispositivos, tornando-a mais fácil de gerir e aumentando a sua fiabilidade e o seu tempo de vida

A critical analysis of research potential, challenges and future directives in industrial wireless sensor networks

In recent years, Industrial Wireless Sensor Networks (IWSNs) have emerged as an important research theme with applications spanning a wide range of industries including automation, monitoring, process control, feedback systems and automotive. Wide scope of IWSNs applications ranging from small production units, large oil and gas industries to nuclear fission control, enables a fast-paced research in this field. Though IWSNs offer advantages of low cost, flexibility, scalability, self-healing, easy deployment and reformation, yet they pose certain limitations on available potential and introduce challenges on multiple fronts due to their susceptibility to highly complex and uncertain industrial environments. In this paper a detailed discussion on design objectives, challenges and solutions, for IWSNs, are presented. A careful evaluation of industrial systems, deadlines and possible hazards in industrial atmosphere are discussed. The paper also presents a thorough review of the existing standards and industrial protocols and gives a critical evaluation of potential of these standards and protocols along with a detailed discussion on available hardware platforms, specific industrial energy harvesting techniques and their capabilities. The paper lists main service providers for IWSNs solutions and gives insight of future trends and research gaps in the field of IWSNs

Designs for the Quality of Service Support in Low-Energy Wireless Sensor Network Protocols

A Wireless Sensor Network (WSN) consists of small, low cost, and low energy sensor nodes that cooperatively monitor physical quantities, control actuators, and perform data processing tasks. A network may consist of thousands of randomly deployed self-configurable nodes that operate autonomously to form a multihop topology. This Thesis focuses on Quality of Service (QoS) in low-energy WSNs that aim at several years operation time with small batteries. As a WSN may include both critical and non-critical control and monitoring applications, QoS is needed to make intelligent, content specific trade-offs between energy and network performance. The main research problem is defining and implementing QoS with constrained energy budget, processing power, communication bandwidth, and data and program memories. The problem is approached via protocol designs and algorithms. These are verified with simulations and with measurements in practical deployments. This Thesis defines QoS for WSNs with quantifiable metrics to allow measuring and managing the network performance. The definition is used as a basis for QoS routing protocol and Medium Access Control (MAC) schemes, comprising dynamic capacity allocation algorithm and QoS support layer. Dynamic capacity allocation is targeted at reservation based MACs, whereas the QoS support layer operates on contention based MACs. Instead of optimizing the protocols for a certain use case, the protocols allow configurable QoS based on application specific requirements. Finally, this Thesis designs sensor self-diagnostics and diagnostics analysis tool for verifying network performance. Compared to the related proposals on in-network sensor diagnostics, the diagnostics also detects performance problems and identifies reasons for the issues thus allowing the correction of problems. The results show that the developed protocols allow a clear trade-off between energy, latency, throughput, and reliability aspects of QoS while incurring a minimal overhead. The feasibility of results for extremely resource constrained WSNs is verified with the practical implementation with a prototype hardware platform having only few Million Instructions Per Second (MIPS) of processing power and less than a hundred kBs data and program memories. The results of this Thesis can be used in the WSN research, development, and implementation in general. The developed QoS definition, protocols, and diagnostics tools can be used separately or adapted to other applications and protocols

Energy Efficient Routing Algorithms for Wireless Sensor Networks and Performance Evaluation of Quality of Service for IEEE 802.15.4 Networks

The popularity of Wireless Sensor Networks (WSN) have increased tremendously in recent time due to growth in Micro-Electro-Mechanical Systems (MEMS) technology. WSN has the potentiality to connect the physical world with the virtual world by forming a network of sensor nodes. Here, sensor nodes are usually battery-operated devices, and hence energy saving of sensor nodes is a major design issue. To prolong the network‘s lifetime, minimization of energy consumption should be implemented at all layers of the network protocol stack starting from the physical to the application layer including cross-layer optimization. In this thesis, clustering based routing protocols for WSNs have been discussed. In cluster-based routing, special nodes called cluster heads form a wireless backbone to the sink. Each cluster heads collects data from the sensors belonging to its cluster and forwards it to the sink. In heterogeneous networks, cluster heads have powerful energy devices in contrast to homogeneous networks where all nodes have uniform and limited resource energy. So, it is essential to avoid quick depletion of cluster heads. Hence, the cluster head role rotates, i.e., each node works as a cluster head for a limited period of time. Energy saving in these approaches can be obtained by cluster formation, cluster-head election, data aggregation at the cluster-head nodes to reduce data redundancy and thus save energy. The first part of this thesis discusses methods for clustering to improve energy efficiency of homogeneous WSN. It also proposes Bacterial Foraging Optimization (BFO) as an algorithm for cluster head selection for WSN. The simulation results show improved performance of BFO based optimization in terms of total energy dissipation and no of alive nodes of the network system over LEACH, K-Means and direct methods. IEEE 802.15.4 is the emerging next generation standard designed for low-rate wireless personal area networks (LR-WPAN). The second part of the work reported here in provides performance evaluation of quality of service parameters for WSN based on IEEE 802.15.4 star and mesh topology. The performance studies have been evaluated for varying traffic loads using MANET routing protocol in QualNet 4.5. The data packet delivery ratio, average end-to-end delay, total energy consumption, network lifetime and percentage of time in sleep mode have been used as performance metrics. Simulation results show that DSR (Dynamic Source Routing) performs better than DYMO (Dynamic MANET On-demand) and AODV (Ad–hoc On demand Distance Vector) routing protocol for varying traffic loads rates

QoS improvement in TCP/IP-based wireless sensor networks using cross-layer optimization

Dissertação de Mestrado, Engenharia Informática, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2015Internet of Things (IoT) is becoming a reality and new and advanced applications are expected to emerge. For applications with reliability needs to work well in IoT environments, robust data transportation is required. Approaches like TCP are known for not being adequate in sensor network environments, while UDP has been included in the 6LoWPAN stack allowing low-power and limited processing devices to participate in the IoT. However, UDP provides no reliability. One way of providing reliability is to use link-layer acknowledgements but this mechanism may lead to an inefficient use of resources if used unconditionally throughout all the network. Another way is to request the confirmation of messages sent, done at the application layer, but this is an end-to-end process that can only be applied for specific message type transactions. If used for all data then there will be long delays and inefficient use of resources also. Here we address the design of a cross-layer reactive mechanism that improves reliability of data delivery, in order to support applications that require some reliability level when delivering data notifications. This mechanism introduces link layer reliability at specific nodes, gradually and only when needed, having no scaling problems. Results show that this mechanism can improve data delivery and improve the use of network resources.Erasmus Mundus Iran Iraq Yemen (EMIIY

Keberkesanan program simulasi penapis sambutan dedenyut terhingga (FIR) terhadap kefahaman pelajar kejuruteraan elektrik

Kefahaman merupakan aset bagi setiap pelajar. Ini kerana melalui kefahaman pelajar dapat mengaplikasikan konsep yang dipelajari di dalam dan di luar kelas. Kajian ini dijalankan bertujuan menilai keberkesanan program simulasi penapis sambutan dedenyut terhingga (FIR) terhadap kefahaman pelajar kejuruteraan elektrik FKEE, UTHM dalam mata pelajaran Pemprosesan Isyarat Digital (DSP) bagi topik penapis FIR. Metodologi kajian ini berbentuk kaedah reka bentuk kuasi�eksperimental ujian pra-pasca bagi kumpulan-kumpulan tidak seimbang. Seramai 40 responden kajian telah dipilih dan dibahagi secara rawak kepada dua kllmpulan iaitu kumpulan rawatan yang menggunakan program simulasi penapis FIR dan kumpulan kawalan yang menggunakan kaedah pembelajaran berorientasikan modul pembelajaran DSP UTHM. Setiap responden menduduki dua ujian pencapaian iaitu ujian pra dan ujian pasca yang berbentuk kuiz. Analisis data berbentuk deskriptif dan inferens dilakllkan dengan menggunakan Peri sian Statistical Package for Social Science (SPSS) versi 11.0. Dapatan kajian menunjukkan kedua-dua kumpulan pelajar telah mengalami peningkatan dari segi kefahaman iaitu daripada tahap tidak memuaskan kepada tahap kepujian selepas menggunakan kaedah pembelajaran yang telah ditetapkan bagi kumpulan masing-masing. Walaubagaimanapun, pelajar kumpulan rawatan menunjukkan peningkatan yang lebih tinggi sedikit berbanding pelajar kumpulan kawalan. Namun begitu, dapatan kajian secara ujian statistik menunjukkan tidak terdapat perbezaan yang signifikan dari segi pencapaian markah ujian pasca di antara pelajar kumpulan rawatan dengan pelajar kumpulan kawalan. Sungguhpun begitu, penggunaan program simulasi penapis FIR telah membantu dalam peningkatan kefahaman pelajar mengenai topik penapis FIR

Wireless Technologies for Indoor Asset Positioning

The Positioning of assets in a manufacturing industry is one of the milestones in the process to increase the visibility inside the factory and improve the current manufacturing practices. Furthermore, in order to cope with the high mobility of the assets in a factory, the utilization of wireless technologies has been increased in the past few years in order to develop the positioning applications. However, the utilization of these technologies must not increase the complexity of the manufacturing systems. Therefore, the utilization of a common network protocol such as the Internet Protocol is preferred. The theoretical part of this thesis work presents a general description of the wireless technologies used in industrial environments. Additionally, it discusses the different methodologies and algorithms used for the positioning of assets applications in wireless networks in more detail. Furthermore, an introduction to the latest efforts and systems developed to address the problem of position estimation of assets in wireless networks is provided. In order to understand the realization of the IP-based wireless sensor networks, a brief review of the operating systems supporting this characteristic is presented. Finally a survey about the IP-ready wireless sensor network is performed in order to select the most suitable platform to use in the practical part of this work. The practical part of this thesis work focuses on the implementation of a real-time position estimation tool for manufacturing assets based on a Wireless Sensor Network for indoor environments. The main purpose is to estimate the position of a pallet allocated on a light assembly manufacturing line. In addition, the wireless sensor network utilizes the Internet Protocol version 6 as the networking protocol. Furthermore, the estimation parameter utilized by the tool is the received signal strength. Consequently, the position estimation methodologies based on the received signal strength are implemented by this tool. Finally, the position estimation tool was tested which is documented in the results section. /Kir1

Synchronous and Concurrent Transmissions for Consensus in Low-Power Wireless

With the emergence of the Internet of Things, autonomous vehicles and the Industry 4.0, the need for dependable yet adaptive network protocols is arising. Many of these applications build their operations on distributed consensus. For example, UAVs agree on maneuvers to execute, and industrial systems agree on set-points for actuators.Moreover, such scenarios imply a dynamic network topology due to mobility and interference, for example. Many applications are mission- and safety-critical, too.Failures could cost lives or precipitate economic losses.In this thesis, we design, implement and evaluate network protocols as a step towards enabling a low-power, adaptive and dependable ubiquitous networking that enables consensus in the Internet of Things. We make four main contributions:- We introduce Orchestra that addresses the challenge of bringing TSCH (Time Slotted Channel Hopping) to dynamic networks as envisioned in the Internet of Things. In Orchestra, nodes autonomously compute their local schedules and update automatically as the topology evolves without signaling overhead. Besides, it does not require a central or distributed scheduler. Instead, it relies on the existing network stack information to maintain the schedules.- We present A2 : Agreement in the Air, a system that brings distributed consensus to low-power multihop networks. A2 introduces Synchrotron, a synchronous transmissions kernel that builds a robust mesh by exploiting the capture effect, frequency hopping with parallel channels, and link-layer security. A2 builds on top of this layer and enables the two- and three-phase commit protocols, and services such as group membership, hopping sequence distribution, and re-keying.- We present Wireless Paxos, a fault-tolerant, network-wide consensus primitive for low-power wireless networks. It is a new variant of Paxos, a widely used consensus protocol, and is specifically designed to tackle the challenges of low-power wireless networks. By utilizing concurrent transmissions, it provides a dependable low-latency consensus.- We present BlueFlood, a protocol that adapts concurrent transmissions to Bluetooth. The result is fast and efficient data dissemination in multihop Bluetooth networks. Moreover, BlueFlood floods can be reliably received by off-the-shelf Bluetooth devices such as smartphones, opening new applications of concurrent transmissions and seamless integration with existing technologies

A study into prolonging Wireless Sensor Network lifetime during disaster scenarios

A Wireless Sensor Network (WSN) has wide potential for many applications. It can be employed for normal monitoring applications, for example, the monitoring of environmental conditions such as temperature, humidity, light intensity and pressure. A WSN is deployed in an area to sense these environmental conditions and send information about them to a sink. In certain locations, disasters such as forest fires, floods, volcanic eruptions and earth-quakes can happen in the monitoring area. During the disaster, the events being monitored have the potential to destroy the sensing devices; for example, they can be sunk in a flood, burnt in a fire, damaged in harmful chemicals, and burnt in volcano lava etc. There is an opportunity to exploit the energy of these nodes before they are totally destroyed to save the energy of the other nodes in the safe area. This can prolong WSN lifetime during the critical phase. In order to investigate this idea, this research proposes a new routing protocol called Maximise Unsafe Path (MUP) routing using Ipv6 over Low power Wireless Personal Area Networks (6LoWPAN). The routing protocol aims to exploit the energy of the nodes that are going to be destroyed soon due to the environment, by concentrating packets through these nodes. MUP adapts with the environmental conditions. This is achieved by classifying four different levels of threat based on the sensor reading information and neighbour node condition, and represents this as the node health status, which is included as one parameter in the routing decision. High priority is given to a node in an unsafe condition compared to another node in a safer condition. MUP does not allow packet routing through a node that is almost failed in order to avoid packet loss when the node fails. To avoid the energy wastage caused by selecting a route that requires a higher energy cost to deliver a packet to the sink, MUP always forwards packets through a node that has the minimum total path cost. MUP is designed as an extension of RPL, an Internet Engineering Task Force (IETF) standard routing protocol in a WSN, and is implemented in the Contiki Operating System (OS). The performance of MUP is evaluated using simulations and test-bed experiments. The results demonstrate that MUP provides a longer network lifetime during a critical phase of typically about 20\% when compared to RPL, but with a trade-off lower packet delivery ratio and end-to-end delay performances. This network lifetime improvement is crucial for the WSN to operate for as long as possible to detect and monitor the environment during a critical phase in order to save human life, minimise loss of property and save wildlife